BIOCHEM PART 4 - electron transport chain

RESPIRATION

Electrons from reduced Nicotinamides (NADH) and flavins (FADH2) in the mitochondrial matrix are transferred to molecular oxygen in a process called ____

Respiratory complexes

___ are membrane embedded enzymes that perform redox reactions to capture the free energy from the reduced co-enzyme

Complex I

NADH DEHYDROGENASE (NADH-Q Reductase)

Complex II

SUCCINATE DEHYDROGENASE (Succinate-Q Reductase)

Complex III

CYTOCHROME b-c (QH2- Cytochrome C reductase)

Complex IV

known as Cytochrome C oxidase

Auxiliaries

are small molecules that serve to transport electrons between these respiratory complexes

Co-enzyme Q10 or UBIQUINONE

An auxiliary that transport electrons from CI-CII & CII-CIII

Cytochrome C

An auxiliary that transport electrons from CIII-CIV

Electron Transport Chain

Respiratory complexes + Auxiliaries =

4

Complex I pumps ___ H+

4

Complex III pumps ___ H+

2

Complex IV pumps ___ H+

free energy

In the concept of Electron Transport Chain:

The energy is temporarily stored in a gradient of protons and electrical voltage across the inner mitochondrial membrane and when the H+ move back to the matrix, they give up ______

Water

What is the product of reduction of oxygen?

ATP synthase

This uses the stored energy to make ATP through phosphorylation

• Substrate-level Phosphorylation (SLP)

• Oxidative Phosphorylation

2 Types of Phosphorylation

Substrate-level Phosphorylation

• A type of Phosphorylation that occurs in Glycolysis

• When a substrate is converted to another substrate, ATP is produced (Pi is transferred to ADP)

• ex. 1,3 Biphospho Glycerate → 3 phospho glycerate

Oxidative Phosphorylation

• A type of Phosphorylation that is combination of mitochondrial ATP synthesis and oxidation of reduced co-enzymes

• major source of ATP for aerobic organisms

ATP Synthase

• Makes ATP from ADP and

• Pi Embedded in the inner mitochondrial membrane

Molecular Oxygen

What is the final electron acceptor of ETC?

ATP and H2O

What are the final products of ETC?

Inner mitochondrial membrane

Respiratory complexes are enzymes embedded in the _

High

innermembrane space has a ___ hydrogen ion concentration

Low

mitrochondrial matrix space has a ___ hydrogen ion concentration

Complex II

FADH2 is not as good at donating electrons as NADH, so it passes through

Complex I

NADH is very good at donating electrons in redox reactions (that is, its electrons are at a high energy level), so it can transfer its electrons directly to____ , turning back into NAD+